1. Chapter 10: Mendel & Meiosis
Week 18 notes
Chapter 10: Mendel & Meiosis

2. Monday/ Tuesday

3. Warm-Up What is a chromosome? What is one segment of DNA called?
What is genetics?

4. Agenda Section 10.1 (Mendel’s Laws of Heredity) Lesson & Notes
Punnett Square Practice
Group Research Activity
Kahoot! to reinforce concepts (if time allows)
Homework:
Section 10.1 Assessment Questions #1-5

5. 10.1: Mendel’s Laws of Heredity
Genetics: the branch of Biology that studies heredity
Heredity: the passing on of traits (characteristics) from parents to offspring
Gametes: sex cells (males- sperm; females- eggs)
Zygote: fertilized cell (sperm + egg)

6. 10.1: Mendel’s Laws of Heredity
Gregory Mendel: guy that first predicted how traits are passed from one generation to the next
Mendel used a pea plant for his experiments
He often transferred pollen from one plant to another plant with different traits. This is called making a cross.

8. 10.1: Mendel’s Laws of Heredity
Allele: different forms of a gene
A plant can have 2 alleles for tallness (TT), 2 alleles for shortness (tt), or 1 allele for tallness & one for shortness (Tt)
Dominant vs. Recessive: dominant traits overpower recessive ones
Dominant alleles are represented by a capital letter; recessive alleles are represented by a lowercase letter

9. 10.1: Mendel’s Laws of Heredity
Let’s say…
T: dominant allele for tallness
t: recessive allele for shortness
SHORT OR TALL?? TT tt Tt

10. 10.1: Mendel’s Laws of Heredity

11. 10.1: Mendel’s Laws of Heredity
Mendel’s 1st Law…
Law of Segregation:
Everyone has 2 alleles (versions) of a gene
Each gamete (sex cell) receives one of these alleles

12. 10.1: Mendel’s Laws of Heredity
Genotype: the genes you have
In other words, the allele combination you have
Ex: TT, Tt, or tt
Phenotype: the genes we see
Ex: tall, short, brown eyes
Homozygous: 2 of the same allele (TT, tt)
Heterozygous: 2 different alleles (Tt)

13. 10.1: Mendel’s Laws of Heredity

14. 10.1: Mendel’s Laws of Heredity
Mendel’s 2nd Law…
Law of Independent Assortment:
Genes for different traits are inherited independently
Ex: blonde hair & blue eyes (if you get one, you won’t necessarily get the other)

15. 10.1: Mendel’s Laws of Heredity
Punnett Squares!

16. Punnett Square Practice
Right handedness is a dominant gene. Let’s call it “R”
Left handedness is a recessive gene. Let’s call it “r”
Suppose a mother is right handed (RR) and a father is right handed (Rr). What is the probability that they will have a left handed kid?

17. Punnett Square Practice
Tongue rolling is a dominant gene. Let’s call it “T”
Not being able to roll your tongue is a recessive gene. Let’s call it “t”
Suppose a mother can’t roll her tongue (she is homozygous recessive). The father can roll his tongue and he is heterozygous. How likely is it that they will have a tongue-rolling kid?

18. Group Research Activity
With your groups, research one of the following genetic disorders. What is it? What causes it? Facts about it? Treatment?
Down syndrome
Polydactylism
Color blindness
Tay-Sachs disease
Cri du chat syndrome
Angelman syndrome